Front wheel for a handcart

ABSTRACT

A front wheel structure for a handcart includes a link block having a wheel bracket pivotally attached to an underside thereof with a wheel being rotatably retained in the wheel bracket. A positive stop is slidingly received in a vertical slot defined in the link block and has a head formed at a top end on a first side thereof and a lip formed at a bottom on the first side. In an uppermost position of the positive stop, the bottom thereof is above a sidewall of the wheel bracket such that the wheel bracket can pivot freely. In a lowermost position of the positive stop, the bottom thereof impedes the sidewall of the wheel bracket such that it cannot pivot. A brake is pivotally attached at a top of the wheel bracket and can urge against a periphery of the wheel to.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a front wheel structure, and moreparticularly to a handcart.

2. Description of Related Art

Handcarts are popular devices for shopping etc. It is found thatconventional hand carts fall into two categories of wheel types--fixedand pivotable.

The pivotable type has the advantage of good maneuverability, enablingthe cart to be steered easily around obstacles, corners etc. but has thedisadvantage of, when being used on a sidewalk with a transverseincline, it is difficult to prevent the handcart from veering away fromthe intended longitudinal path of travel. Although the fixed wheel typeovercomes the disadvantage of undesired drift it lacks themaneuverability required in a crowded environment. A conventionalhandcart is shown in FIGS. 6 and 7. The handcart comprises two rearwheels 91 pivotally disposed to the rear end, a handle 92, two frontwheels 94 disposed between both ends of the handle 92, a pivot rod 93and a base rod 95 located above the pivot rod 93.

As shown in FIG. 7, when the handcart is in erected, a bottom front endof the handcart frame is rested on the base rod 95, whereby the handcartframe is supported only by the base rod 95.

However, by such an arrangement, there are still a few shortcomings inthe conventional handcart. Firstly, the front wheels 94 are rigidlyfitted to handle 92, so it is difficult to turn the handcart; secondly,the handcart has no brake means; thirdly, as the handcart frame is onlysupported by a base rod 95, the load carrying capacity is notsufficient.

Thus, there has been a long and unfulfilled need for a hand cart whichis able to be adjusted from a pivotable status to a fixed wheel statuswhen the local environment requires it.

The present invention has arisen to mitigate and/or obviate theabove-mentioned disadvantages of the conventional handcart.

SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a frontwheel structure for a handcart which can be switched between a fixedstate and a pivotable state and has a sufficient load carrying capacity.

Another objective of the present invention is to provide a front wheelstructure for a handcart which has a brake function.

In accordance with one aspect of the present invention, there isprovided a front wheel structure for a handcart which comprises a linkblock having an extension portion with a first hole vertically definedin a bottom thereof, a slot vertically defined inside of said linkblock, a positive stop movably inserted into the slot of the link block,a front wheel assembly, and an axle rotatably attached to the top of thewheel assembly by a bearing, said axle received in the first hole of thelink block.

The link block has a protrusion portion formed on a rear end thereof,the protrusion portion having a second hole transversely defined thereinand a sleeve extending from a top end thereof.

Additionally, the front wheel assembly includes a wheel bracket, a frontwheel rotatably disposed in the wheel bracket and a brake blockpivotally attached to the wheel bracket by a pivot rod.

Further objectives and advantages of the present invention will becomeapparent from a careful reading of the detailed description providedhereinbelow, with appropriate reference to the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a front wheel structure for a handcart inaccordance with the present invention;

FIG. 2 is a cross-sectional view of the front wheel structure inaccordance with the present invention;

FIG. 3 is a perspective view of the front wheel structure as shown inFIG. 1;

FIG. 4 is an operational view showing the relationship of the brakeblock and the front wheel.

FIG. 5 is a perspective view of the front wheel structure in accordancewith the present invention attached to the handcart;

FIG. 6 is a perspective view of a conventional handcart in closedconfiguration; and

FIG. 7 is a perspective view of the conventional handcart of FIG. 6 inerected configuration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-5, and initially to FIGS. 1-3, a front wheelstructure in accordance with the present invention is provided for ahandcart which comprises a link block 10, an axle 20, and a wheelassembly 30.

The link block 10 is preferably made of plastic material. The link block10 has an extension portion 11 with a first hole 12 vertically definedtherein and in communication with a bottom thereof. The link block 10has a protrusion portion 13 upwardly and obliquely formed on a rearportion thereof. A second hole 14 is transversely defined through theprotrusion portion 13 and a sleeve 15 extends integrally from a top endof the protrusion portion 13. A periphery defining the first hole 12 hasa neck portion 120 which has an inner diameter smaller than a diameterof the first hole 12. A longitudinal axis 12' of the first hole 12 isoffset from a longitudinal axis 15' of the sleeve 15, as shown in FIG.2.

Furthermore, a slot 16 is vertically defined inside of the link block 10near a first sideface thereof. An opening 160 which is in communicationwith the slot 16 is defined in the first sideface of the link block 10.A positive stop 17 is received in the slot 16. A thickness of thepositive stop 17 is slightly smaller than a width of the slot 16,whereby the positive stop 17 can be slidingly received in the slot 16.Additionally, the positive stop 17 has a head portion 170 formed on afirst side thereof and a body portion. When the positive stop 17 iscompletely received in the slot 16, the head portion 170 is receivedwithin the opening 160 for limiting downward travel of the positive stop17. As shown in FIG. 2, the positive stop 17 has a resilient lip 171formed on a bottom of the first side of the body portion thereof forpreventing the positive stop 17 from being completely extended out ofthe slot 16. A ridge 172 is formed on an upper end of a second sideopposite to the first side of the positive stop 17, the ridge 172 buttsagainst an inner wall defining the slot 16 for retaining the positivestop 17 in an upper most position. When the positive stop 17 is in alower most position, a lower end thereof extends beyond the bottom ofthe link block 10 and butts against a first sidewall of a wheel bracket31 to impede the wheel bracket 31 from pivoting freely. When thepositive stop 17 is moved to an upper most position the lower end of thepositive stop 17 is disengaged from the side wall of the wheel bracket31, the wheel bracket 31 can pivot freely again.

The wheel assembly 30 is fitted to the link block 10 by the axle 20extending therethrough. The axle 20 projects upwardly from a top of thewheel bracket 31 and is offset towards the first side thereof. A bearing25 is disposed between the axle 20 and the wheel assembly 30, wherebythe axle 20 can rotate smoothly with respect to wheel assembly 30. Theaxle 20 has a diameter slightly smaller than the diameter of the firsthole 12 of the link block 10. A recess 21 is sized and shaped in theaxle 20 to receive the neck portion 120. It is to be noted thatresilience in the materials from which the axle 20 and the link block 10are made permits a distal tip of the axle to extend beyond the neckportion 120. The neck portion 120 can urge against the axle 20 when theaxle 20 extends through the first hole 12 until the neck portion 120 isreceived within the recess 21 of the axle 20, whereby the axle 20 can besecurely received within the first hole 12 (as shown in FIG. 3).

As stated earlier the wheel assembly 30 includes the wheel bracket 31which comprises a front wheel 32 and a brake block 34. The wheel bracket31 is substantially U-shaped in form and the front wheel 32 is rotatablydisposed therein. The brake block 34 has a first end and a second endand is pivotally attached to the wheel bracket 31 by a pivot arm 33transversely extending through the first end. The brake block 34 has afirst inclined face 340 and a second inclined face 341 formed on aninner face at the first end thereof, whereby the first inclined face 340is receivable against a peripheral surface of the front wheel 32. Thesecond inclined face 341 is sized and shaped to be received by anunderface of the wheel bracket 31. The brake block 34 has an extensionportion which extends beyond the wheel bracket 31 enabling the user tocontrol the brake block 34.

As shown in FIG. 4, weight distribution of the brake block 34 result inthe second thereof being inclined downwardly such that the break block34 is disengaged from the wheel 32 and the wheel is free to rotate, asshown in phantom line. When the brake block 34 is urged to move upwardlyby the user, the second end of the brake block 34 is positioned higherthan the first end thereof such that the first inclined face 340 buttsagainst the peripheral surface of the wheel 32 and the second inclinedface 341 butts against a front end of the underface of the wheel bracket31 to limit rotation of the wheel 32. The wheel 32 is subsequentlyreleased to rotate by means of pushing the wheel assembly 30 in adirection opposite to an original direction of travel without needing todirectly operate the brake block 34.

Referring to FIG. 5, showing the present invention fitted to thehandcart, a push rod 40 of the handcart is inserted into the sleeve 15of the link block 10 and each end of a strut 42 disposed at the bottomof the handcart frame 41 is received in the second hole 14.Simultaneously, a bottom corner of the handcart frame 41 is rested onthe extension portion 11 of the link block 10.

From the foregoing, it is seen that the objects hereinbefore set forthmay readily and efficiently be attained, and since certain changes maybe made in the above construction and different embodiments of theinvention without departing from the scope thereof, it is intended thatall matter contained in the above description or shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

What is claimed is:
 1. A front wheel structure for a handcartcomprising:a link block comprising an extension portion with a firsthole vertically defined in a bottom thereof, a protrusion portion formedon a rear end thereof, the protrusion portion defining a second holdtransversely extending therethrough and a sleeve extending upwardly andobliquely from the protrusion portion for being fixedly attached to aframe of the handcart at a first end thereof; a wheel assembly having awheel attachment means pivotally coupled to a second end of the linkblock, and a wheel rotatably retained in the wheel attachment means; abrake means operably connected to a first end of the wheel attachmentmeans to selectively engage with the wheel and brake it; and arrestingmeans operably received in the link block and the link block furtherincluding a slot vertically defined near a first face thereof forreceiving the arresting means, and an opening defined in the first sideand in communication with the slot, thereby the arresting means beingselectively movable between a lowermost position, at which a bottom endof the arresting means engages with the wheel attachment means tothereby prevent the wheel assembly from freely pivoting relative to thelink block, and an uppermost position, at which the arresting meansdisengages form the wheel attachment means to free the wheel from beingconstrained.
 2. The front wheel structure for a handcart as claimed inclaim 1 wherein the arresting means is a positive stop comprising a bodyportion, a head portion formed at a top of a first side thereof andmatingly received in the opening of the link block to hold the positivestop in the lowermost position, a lip formed at a bottom of the firstside thereof and being engagable with a bottom of the link block toprevent the positive stop from leaving the slot when moving upward, anda ridge formed on a second side opposite to the first side and buttingagainst an inner wall defining the slot to hold the stop in theuppermost position.
 3. The front wheel structure for a handcart asclaimed in claim 2 wherein an axis of the sleeve offsets from an axis ofthe first hole of the link block.
 4. The front wheel structure for ahandcart as claimed in claim 1, wherein the wheel attachment meansincludes an axle extending vertically upward and which is pivotallyreceived in the second hole of the link block.
 5. A front wheelstructure for a handcart comprising:a link block fixedly attached to aframe of the handcart at a first end thereof; an arresting meansoperably received in the link block; a wheel assembly having a wheelattachment means pivotally coupled to a second end of the link block,and a wheel rotatably retained in the wheel attachment means; a brakemeans operably connected to a first end of the wheel attachment means toselectively engage with the wheel and brake it thereby; the arrestingmeans being selectively movable between a lowermost position, at which abottom end of the arresting means engages with the wheel attachmentmeans to thereby prevent the wheel assembly from freely pivotingrelative to the link block, and an uppermost position, at which thearresting means disengages from the wheel attachment means to free thewheel from being constrained, said link block comprising an extensionportion with a first hole vertically defined in a bottom thereof, a slotvertically defined near a first face thereof for receiving the arrestingmeans, an opening defined in the first side and in communication withthe slot, a protrusion portion formed on a rear end thereof, theprotrusion portion defining a second hole transversely extendingtherethrough and a sleeve extending upwardly and obliquely from theprotrusion portion for coupling to the frame of the handcart.